Standardization works of international mobile telecommunication (IMT)-advanced which is a next generation (i.e., post 3rd generation) mobile communication system are carried out in the international telecommunication union radio communication sector (ITU-R). The IMT-advanced aims at support of an Internet protocol (IP)-based multimedia service with a data transfer rate of 1 Gbps in a stationary or slowly moving state or 100 Mbps in a fast moving state.
3rd generation partnership project (3GPP) is a system standard satisfying requirements of the IMT-advanced, and prepares LTE-advanced which is an improved version of long term evolution (LTE) based on orthogonal frequency division multiple access (OFDMA)/single carrier-frequency division multiple access (SC-FDMA) transmission. The LTE-advanced is one of promising candidates for the IMT-advanced.
The LTE-advanced (LTE-A) may include a new technology, e.g., relay, coordinated multiple point transmission/reception (CoMP), etc., and can support an improved technology, e.g., multiple input multiple output (MIMO) extension which uses a more number of transmit antennas than the number of transmit antennas used in the LTE. A relay station is a device for relaying a signal between a base station and a user equipment, and is used for cell coverage extension and throughput enhancement of a wireless communication system.
Backward compatibility with a user equipment, a network, or the like which is designed to operate in the legacy LTE is one of factors to be considered in the LTE-A. That is, the LTE-A preferably supports operations of the user equipment, the network, or the like which is designed to operate in the LTE. From this aspect, designing of a subframe structure, that is, allocation of radio resources in a subframe, is a matter to be considered.
In addition, the relay station decodes a physical downlink control channel (PDCCH) allocated to the relay station by performing blind decoding in a radio resource region allocated in a subframe. Further, the relay station receives data by finding a physical downlink shared channel (PDSCH) allocated to the relay station through the PDCCH. However, it is ineffective to perform blind decoding by the relay station throughout a full frequency band in a frequency domain of a subframe.
Accordingly, there is a need for a subframe structure and a method capable of effectively allocating radio resources to a relay station while providing backward compatibility with a legacy user equipment in a wireless communication system employing the relay station.